The need for transfilling liquid drugs exists in various medical fields. Particularly, a considerable and increasing number of persons with diabetes (PwD) rely on Continuous Subcutaneous Insulin Infusion (CSII) via miniaturized and computer-controlled infusion pumps to supply insulin to the body in a continuous way night and day. In classic systems of this type, a generally cylindrical insulin glass or plastic cartridge is emptied by displacing a piston via a plunger rod in a controlled way (syringe-driver pump). In recent times, however, a number of alternative approaches have and are being proposed and developed which use flexible or semi-flexible insulin reservoirs, such as bags or pouches rather than rigid containers. Examples for such flexible or semi-flexible containers are disclosed, for example, in the EP2179755 B1. Typical filling volumes for such insulin reservoirs lay in a range of, for example, 1 ml to 4 ml. This amount of insulin is sufficient for a number of days of therapy for most PwDs. Mainly for safety and regulatory reasons, the reservoirs are generally one-way products that are discarded and replaced after a single use.